Add x86_64 installation instructions

[harryhobson]

Firstly thankyou for the wonderful software and documentation you have, I have been using Fedora for many years. Also apologies if any of the below is not completely accurate, it's just my understanding from reading various documentation.

TLDR: there are no physical device install instructions for Fedora IoT x86_64 here.

Would it be possible to add instructions for using the Fedora Media Writer to install Fedora IoT on x86_64?

Longer version:

I initially installed Fedora IoT on my raspberry pi (ARM) and found the documentation very helpful. More recently I wished to install Fedora IoT on an x86_64 computer rather than ARM, however I noticed there is no information in the physical device setup relating to x86_64. The only information I could find about x86_64 is in the 'Setting up a Virtual Machine' which is not applicable to this situation with a physical computer.

However, after a fair bit of playing around I discovered that the Fedora Media Writer supports Fedora IoT, which essentially lets Fedora IoT be booted as a live disk. From the Fedora IoT documentation I did not realise the following:

1. That the Fedora Media Writer can be used to install Fedora IoT on a device such as a USB.
2. The Fedora IoT iso (at least the x86_64 version I used) is a live image that can also install the operating system on another disk